Effect of Arbuscular Mycorrhizal Fungi, Selenium and Biochar on Photosynthetic Pigments and Antioxidant Enzyme Activity Under Arsenic Stress in Mung Bean (Vigna radiata).

Md Anamul Hoque,Golam Jalal Ahammed,Mohammad Zahangeer Alam,Lynne Carpenter-Boggs,Rebecca Mcgee

doi:10.3389/fphys.2019.00193

Abstract

Environmental perturbations alter biochemical compounds in food crops. Arsenic (As), a toxic metalloid, is known to affect the cultivation of food crops in many regions of the world; however, the changes in chlorophyll, catalase (CAT), and proline in response to As stress and the role of stress relief substances remain largely unknown in mung bean (Vigna radiate L.). In this study, biochar (BC), arbuscular mycorrhizal fungi (AMF), and selenium (Se) were applied to soils as stress relief substances (under 30 mg kg-1 As stress), and the effects of BC, AMF, and Se on chlorophyll a, chlorophyll b, total chlorophyll, CAT activity, and proline content were studied in different mung bean genotypes. Under As stress, the chlorophyll a, chlorophyll b, and total chlorophyll contents in BARI mung 3, BARI mung 5, and BARI mung 8 were found statistically similar. Meanwhile, CAT activity increased in comparison to the control due to the application of BC, AMF, and Se in mung bean crops. However, proline was found significantly lower in AMF, BC, and Se-treated mung bean. This indicates that oxidative stress was potentially minimized in As-stressed mung bean crops due to the application of these stress relief substances. Notably, AMF was relatively effective against As stress in comparison to BC and Se. It is concluded that BC, AMF, and Se are all highly effective in enhancing antioxidant defenses as well as the nutritional quality of mung bean crops under As stress.

Highlights

Biochemical compounds in food crops fluctuate with the changes in plant physiological status
Proline content was significantly reduced due to the application of mycorrhiza in citrus plants as well as in mung bean crops (Ying-Ning et al, 2013). These results suggest that osmotic stress is significantly reduced in arbuscular mycorrhizal fungi (AMF)-applied mung bean crops (Swarnakar, 2014)
BC, AMF, and Se were used for the mitigation of As uptake as well as to study the enzymatic activities during As stress conditions

Summary

Introduction

Biochemical compounds in food crops fluctuate with the changes in plant physiological status. Significant changes of biochemical compounds are indicators of environmental perturbations that often cause the deterioration of both yield and quality of food crops (Tripathi and Gautam, 2007). Proline and catalase (CAT) both are sensitive indicators of salt and other environmental stresses in different food crops (Gharsallah et al, 2016). These biochemical parameters change during salt and drought as well as arsenic (As) stress conditions in food crops (Swarnakar, 2014; Sofo et al, 2015). Stress conditions trigger ROS production, leading to the occurrence of oxidative stress in plant cells. CAT is involved in scavenging H2O2 (Horemans et al, 2000) and contributes to the plant defense mechanism against oxidative stress (Gill and Tuteja, 2010; Cheynier et al, 2013)

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Discussion

Conclusion